Bone cutters, such as acetabular reamers, are surgical tools which are used to cut a partial hemispherically-shaped cavity within a bone. In particular, an acetabular reamer is an orthopedic surgical tool used to cut a partial hemispherically-shaped cavity within a pelvic bone for the insertion of a prosthetic cup during an artificial hip joint procedure.
Acetabular reamers must be capable of producing cavities having precise dimensions to ensure the proper positioning of a prosthetic cup within the pelvic bone. As such, traditional reamers, such as those disclosed in U.S. Pat. No. 4,811,632 to Salyer, are constructed having a hemispherical cup-like shape. These prior art reamers are fabricated with a plurality of cutting surfaces that are precisely positioned extending from the curved surface of the curved reamer shell. The hemispherical cup-like body construction provides the reamer with structural rigidity that enables a precise cut. Fabrication of these traditional reamers is often difficult and cost prohibitive. Traditional reamers like that of Salyer require precise positioning of a multitude of cutting surfaces along a curved convex shape of a reamer shell. This requires the use of intricate tooling and expertise. Therefore, because of the high cost of these tools, traditional reamers are often cleaned and sterilized for reuse in multiple surgical procedures.
However, traditional reamers, like Salyer, are often difficult to clean and sterilize. After use, soft tissue embedded in the tool is often difficult to remove. As a result, the surfaces of these reamers may become contaminated with bacteria or micro-organisms which may cause adverse surgical outcomes. Consequently, cutting tools such as those disclosed by Stamp in U.S. patent application Pub. No. 2013/0267957 that are intended for single use have been developed. After such use, the cutting tool is simply discarded.
Single use cutting tools, however, typically lack structural rigidity which may adversely affect patient outcomes. Such structural rigidity minimizes unintended deflection of the cutting edge of the cutting tool that might result in an undesirable patient outcome. Deflection of a portion of the cutting tool, in particular deflection of a cutting edge against the surface of a bone during use could result in an inaccurate cut or deformed bone surface that is not desired. The cutting tool of Stamp, for example, requires the use of an additional support substrate that is used to structurally reinforce the cutting tool and minimize blade deflection.
The bone cutter of the present invention, unlike Stamp, is specifically designed to increase structural rigidity while minimizing the amount of material needed to construct the tool. Thus, improved rigidity while minimizing the amount of material used to construct the reamer provides a minimally invasive cutting tool that is more accurate during use; the unique structural design of the present cutting tool minimizes structural distortion under a mechanical load. Furthermore, by minimizing the amount of material required to construct the tool, the bone cutter of the present invention is more cost effective and easier to manufacture.
Therefore, what is needed is a low cost bone cutter that is easier to manufacture while providing improved structural rigidity.
Still further, what is needed is a method of manufacturing a cost effective bone cutter that provides at least a partial hemispherical form and where the cutter is not as susceptible to mechanical deflection as reamers of the prior art to consequently ensure accurate cutting.